Step 1: Convert the mass of potassium chloride to moles.
moles of KCl = 0.458 g KCl * (1 mol KCl / 74.55 g KCl) = 0.00615 mol KCl
Step 2: Calculate the total volume of the solution in liters.
volume of solution (in L) = 150 mL * (1 L / 1000 mL) = 0.150 L
Step 3: Calculate the moles of chloride anion.
moles of Cl- = 0.00615 mol KCl * (1 mol Cl- / 1 mol KCl) = 0.00615 mol Cl-
Step 4: Calculate the final molarity of chloride anion.
molarity of Cl- = moles of Cl- / total volume of solution
molarity of Cl- = 0.00615 mol / 0.150 L
molarity of Cl- = 0.0410 M
Therefore, the final molarity of chloride anion in the solution is 0.0410 M.